- Efficient Transfer Hydrogenation of Ketones using Methanol as Liquid Organic Hydrogen Carrier
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Herein, we demonstrate an efficient protocol for transfer hydrogenation of ketones using methanol as practical and useful liquid organic hydrogen carrier (LOHC) under Ir(III) catalysis. Various ketones, including electron-rich/electron-poor aromatic ketones, heteroaromatic and aliphatic ketones, have been efficiently reduced into their corresponding alcohols. Chemoselective reduction of ketones was established in the presence of various other reducible functional groups under mild conditions.
- Garg, Nidhi,Paira, Soumen,Sundararaju, Basker
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p. 3472 - 3476
(2020/05/29)
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- Binaphthyl-based chiral ligands: Design, synthesis and evaluation of their performance in enantioselective addition of diethylzinc to aromatic aldehydes
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The design strategy and the performance of binaphthyl-based chiral ligands were evaluated with computation and enantioselective addition of diethylzinc to aromatic aldehydes. Under optimized conditions, enantioselective addition of diethylzinc to aromatic aldehydes provided the desired optically active secondary alcohols in high isolated yields (up to 91%) and excellent enantiomeric excesses (up to 98% ee).
- Yao, Chao,Wu, Piao,Huang, Yue,Chen, Yaoqi,Li, Lin,Li, Yue-Ming
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supporting information
p. 9712 - 9725
(2020/12/28)
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- Isosterically designed chiral catalysts: Rationale, optimization and their application in enantioselective nucleophilic addition to aldehydes
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Proline-based N,N′-dioxide ligands were designed on the basis of isosteric approach, and were successfully applied in enantioselective nucleophilic addition to aldehydes. In the presence of 10 mol% of chiral ligand 1b, enantioselective addition of diethylzinc to aldehydes provided the corresponding secondary alcohols in up to 90% isolated yield and up to 99% ee. Similarly, using 3e as chiral ligand, enantioselective arylation and alkynylation of aldehydes also proceeded readily, leading to the desired chiral alcohols in up to 92% isolated yield at 99% ee and 80% isolated yields and up to 84% ee, respectively. The current work would shed light on expanding the structure diversity in the design of chiral ligands and chiral catalysts.
- Gao, En,Li, Qiao,Duan, Lili,Li, Lin,Li, Yue-Ming
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supporting information
(2020/10/20)
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- NBS-mediated synthesis of β-keto sulfones from benzyl alcohols and sodium arenesulfinates
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An efficient synthetic route towards the synthesis of β-keto sulfones has been developed from secondary benzyl alcohols using N-bromosuccinimide (NBS). The present protocol utilizes NBS as oxidant as well as brominating agent, readily accessible benzyl alcohols and sodium arenesulfinates as the sulfonylating reagent under mild conditions. The control experiments revealed that the reaction proceeds via oxidation of alcohol to ketone, α-bromination of ketone and nucleophilic substitution by sodium arenesulfinate. Furthermore, the efficiency of the methodology was tested with a gram scale reaction and also shown the synthetic utility.
- Muneeswara, Madithedu,Sundaravelu, Nallappan,Sekar, Govindasamy
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supporting information
p. 3479 - 3484
(2019/05/21)
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- Halogen-bonded iodonium ion catalysis: A route to α-hydroxy ketones: Via domino oxidations of secondary alcohols and aliphatic C-H bonds with high selectivity and control
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A domino synthesis of α-hydroxy ketones has been developed from benzylic secondary alcohols employing catalytic iodonium ions stabilized by DMSO. The reaction proceeds through an unprecedented sequential oxidation of alcohols to ketone and its α-hydroxylation in a controlled manner. The spectroscopic evidence establishes the possibility of formation of a stable halogen-bonded adduct between DMSO and iodonium ions.
- Guha, Somraj,Kazi, Imran,Mukherjee, Pranamita,Sekar, Govindasamy
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supporting information
p. 10942 - 10945
(2017/10/13)
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- Manganese complex-catalyzed oxidation and oxidative kinetic resolution of secondary alcohols by hydrogen peroxide
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The highly efficient catalytic oxidation and oxidative kinetic resolution (OKR) of secondary alcohols has been achieved using a synthetic manganese catalyst with low loading and hydrogen peroxide as an environmentally benign oxidant in the presence of a small amount of sulfuric acid as an additive. The product yields were high (up to 93%) for alcohol oxidation and the enantioselectivity was excellent (>90% ee) for the OKR of secondary alcohols. Mechanistic studies revealed that alcohol oxidation occurs via hydrogen atom (H-atom) abstraction from an α-CH bond of the alcohol substrate and a two-electron process by an electrophilic Mn-oxo species. Density functional theory calculations revealed the difference in reaction energy barriers for H-atom abstraction from the α-CH bonds of R- and S-enantiomers by a chiral high-valent manganese-oxo complex, supporting the experimental result from the OKR of secondary alcohols.
- Miao, Chengxia,Li, Xiao-Xi,Lee, Yong-Min,Xia, Chungu,Wang, Yong,Nam, Wonwoo,Sun, Wei
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p. 7476 - 7482
(2017/10/30)
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- Chemo- and Enantioselective Addition and β-Hydrogen Transfer Reduction of Carbonyl Compounds with Diethylzinc Reagent in One Pot Catalyzed by a Single Chiral Organometallic Catalyst
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Using a single chiral phosphoramide-Zn(II) complex as the catalyst, the asymmetric β-H transfer reduction of aromatic α-trifluoromethyl ketones and enantioselective addition of aromatic aldehydes with Et2Zn in one pot were successfully realized, affording the corresponding additive products of secondary alcohols in high yields (up to 99%) with excellent enantioselectivities (up to 98% ee) and the reduction products of α-trifluoromethyl alcohols in good to excellent yields with up to 77% ee.
- Huang, Huayin,Zong, Hua,Bian, Guangling,Song, Ling
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p. 12614 - 12619
(2016/01/09)
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- Synthesis and mesomorphic properties of laterally fluorinated alkyl 4′′-alkylterphenyl-4-yl carbonate liquid crystals
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Fifteen series of homologues of a variety of mono-, di- and trifluorosubstituted alkyl 4′′-alkylterphenyl-4-yl carbonates have been synthesized and their mesomorphic properties have been determined. From among 95 prepared compounds, 40 pure nematogens have been found, as well as 55 mesogens with orthogonal and tilted smectic phases in broad temperature ranges. The type and combination of the LC phase strongly depend on the position and number of the fluorine atoms. Physical properties and correlations between the molecular core fluorosubstitution, the length of the terminal chains and the type and sequence of the liquid crystalline phases, have been determined. The compounds are useful for the formulation of nematic mixtures as well as ferroelectric ones.
- Choluj, Artur,Kula, Przemyslaw,Dabrowski, Roman,Tykarska, Marzena,Jaroszewicz, Leszek
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p. 891 - 900
(2014/01/23)
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- A new pyrrolidine-derived atropisomeric amino alcohol as a highly efficient chiral ligand for the asymmetric addition of diethylzinc to aldehydes
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A highly efficient pyrrolidine-derived atropisomeric amino alcohol, (Sa)-1-[2-diphenylhydroxymethyl-6-(trifluoromethyl)phenyl]-2-(1-pyrrolido)methyl-1H-pyrrole, has been synthesized as a chiral ligand for the enantioselective addition of diethylzinc to some prochiral aldehydes to afford (S)-alcohols. The conversion rates were close to quantitative with good to excellent enantiomeric excesses (up to 95% ee).
- Faigl, Ferenc,Erdélyi, Zsuzsa,Deák, Szilvia,Nyerges, Miklós,Mátrav?lgyi, Béla
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supporting information
p. 6891 - 6894
(2015/02/02)
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- Liquid crystal carbonate and liquid crystal medium containing the same with positive or negative dielectric anisotropy
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A novel liquid crystalline carbonate and the mixture containing the same: wherein R3 is an alkyl (H2n+1Cn) or an alkenyl (H2n?1Cn) group, each of 1 to 12 carbon atoms, the ring A is laterally unsubstituted benze
- -
-
Paragraph 0040
(2013/03/26)
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- Enantioselective addition of diethylzinc to aldehydes by chiral oxazolidine-titanium complex
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A series of chiral oxazolidines derived from (1R, 2S)-cis-1-amino-2-indanol was found to be effective in promoting the asymmetric addition of diethylzinc to aldehydes. Among the ligands developed, it was found that ligand 1b in the presence of Ti(OiPr)4 yielded the highest enantioselectivities when it was applied in the catalytic asymmetric addition of diethylzinc to aldehydes (up to 91% ee).
- Wu, Nan,Bo, Rongcheng,Zhang, Rongli,Jiang, Xi,Wan, Yu,Xu, Zhou,Wu, Hui
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p. 644 - 649
(2013/02/23)
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- Synthesis of novel 1,4-bissulfonamide ligands for enantioselective addition of diethylzinc to aldehydes
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Several novel chiral sulfonamide ligands based on (1R,2S,4R,5S)-1,4- diamino-2,5-dimethylcyclohexane skeleton have been synthesized and their application in the enantioselective addition of diethylzinc to aldehydes was investigated in the presence of Ti(O
- Yang, Minghua,Sun, Jiangtao,Zhu, Chengjian
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experimental part
p. 1697 - 1702
(2012/01/13)
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- L-proline-derived tertiary amino alcohols as chiral ligands for enantioselective addition of diethylzinc to aldehydes
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A series of L-proline derived tertiary amino alcohols was used as chiral ligands in the asymmetric addition reaction of Et2Zn to aldehydes. Among these ligands, it was found that ligand 1b which has the biggest steric and electrondonating substituent at the nitrogen position yielded the highest enantioselectivities when applied in the catalytic asymmetric addition of diethylzinc to p-chlorobenzadehyde. The experiment results of our paper may supply useful experience to help in revealing the relationship between ligand structure and ee values of the products.
- Xu, Zhou,Bo, Rongcheng,Wu, Nan,Wan, Yu,Wu, Hui
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experimental part
p. 582 - 586
(2012/05/31)
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- Ar-BINMOLs with axial and sp3 central chirality - Characterization, chiroptical properties, and application in asymmetric catalysis
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2′-Hydroxy-1,1′-binaphthalene-2-(arylmethanol) (Ar-BINMOLs), a family of new 1,1′-binaphthalene-2,2′-diol derivatives, prepared by a [1,2]-Wittig rearrangement, are introduced as new chiral molecules for the study of the modes of supramolecular aggregatio
- Gao, Guang,Bai, Xing-Feng,Yang, Hua-Meng,Jiang, Jian-Xiong,Lai, Guo-Qiao,Xu, Li-Wen
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supporting information; experimental part
p. 5039 - 5046
(2011/10/09)
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- CAMPHOR-DERIVED BETA-AMINO ALCOHOL COMPOUNDS, METHOD FOR MANUFACTURING THE SAME AND ASYMMETRIC ADDITION OF ORGANOZINC TO ALDEHYDES USING THE SAME
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A novel camphor-derived β-amino alcohol compound is disclosed. The novel camphor-derived β-amino alcohol compound can be used in asymmetric addition of organozinc to aromatic and aliphatic aldehydes, including linear aliphatic ones, thus generating corresponding secondary alcohols in high yields and enantiomeric excess.
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Page/Page column 7-8
(2012/01/13)
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- Alternative method for alkylation of arylpolyhalomethanes with trialkylborane in the presence of magnesium
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Reduction of benzal halide derivatives and α,α,α,-trichloromethylbenzene by magnesium powder in DMAc affords α-halocarbanions which then react with triethylborane to give alkylated products. After oxidation with H2O2-NaOH, secondary
- Condon, Sylvie,Nédélec, Jean-Yves
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supporting information; experimental part
p. 32 - 35
(2010/09/18)
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- Enantioselective addition of diethylzinc to aldehydes catalyzed by d-glucosamine derivatives: Highly pronounced effect of trifluoromethylsulfonamide
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We present the synthesis of β-hydroxy sulfonamides derived from d-glucosamine and their application as ligands in titanium tetraisopropoxide promoted enantioselective addition of diethylzinc to benzaldehyde and selected aromatic and aliphatic aldehydes. The N-trifluoromethylosulfonamido-d-glucosamine derivative is one of the most active ligands known and only 1 mol% of the ligand is sufficient for efficient catalysis of diethylzinc addition. The reaction is highly enantioselective for some aromatic aldehydes and enantiomeric excess up to 99% was obtained.
- Bauer, Tomasz,Smoliński, S?awomir
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experimental part
p. 247 - 251
(2010/11/18)
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- Asymmetric addition of diethylzinc to aldehydes catalyzed by a camphor-derived β-amino alcohol
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The asymmetric addition of diethylzinc to aromatic and aliphatic aldehydes, including linear aliphatic ones, catalyzed by 2 mol % of β-amino alcohol (1S, 2R)-7,7-dimethyl-1-morpholin-4-yl-bicyclo[2.2.1]heptan-2-ol 10 gave the corresponding secondary alcohols in high yields and with up to 94% ee at ambient temperature after 15 min.
- Wu, Zhi-Long,Wu, Hsyueh-Liang,Wu, Ping-Yu,Uang, Biing-Jiun
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experimental part
p. 1556 - 1560
(2009/11/30)
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- Asymmetric reduction of halo-substituted arylalkanones with Rhizopus arrhizus
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The Rhizopus arrhizus-mediated asymmetric reduction of various haloaryl alkanones furnished the respective (S)-carbinols with good to excellent enantioselectivities. It was found that the reaction course was primarily governed by the relative position of the halogen with respect to the carbonyl group, and its size. The relative order of efficacies of the nature of the halogen and their substitution pattern were Br > Cl > F and o- > p- > m-. The ortho-effect was the most predominant factor in the stereochemical outcome of the reaction, which was also confirmed with some non-halo-substituted acetophenones.
- Salvi, Neeta A.,Chattopadhyay, Subrata
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p. 1992 - 1997
(2008/12/22)
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- Method of Synthesizing Key Intermediates for the Production of Camptothecin Derivatives
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The present invention discloses a process for efficient production of 2-amino-5-hydroxypropiophenone corresponding to the AB ring part of camptothecin (CPT) skeleton, which is a key intermediate useful for the total synthesis of camptothecin analogs including 7-Ethyl-10-hydroxy camptothecin and novel intermediates thereof.
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Page/Page column 4
(2008/12/08)
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- Structural optimization of enantiopure 2-cyclialkylamino-2-aryl-1,1- diphenylethanols as catalytic ligands for enantioselective additions to aldehydes
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(Chemical Equation Presented) The structural optimization of a family of modular, enantiopure β-amino alcohol ligands with a common 2-amino-2-aryl-1,1-diphenylethanol skeleton, whose stereogenicity was introduced through the Jacobsen epoxidation of 1,1-diphenyl-2-arylethylenes, has led to the identification of a small set of optimal catalysts with enhanced activity and enantioselectivity in the addition of alkylzinc and arylzinc reagents to aldehydes. Criteria for the discrimination between apparently analogous, highly enantioselective ligands are proposed.
- Rodriguez-Escrich, Sergi,Reddy, Katamreddy Subba,Jimeno, Ciril,Colet, Gisela,Rodriguez-Escrich, Carles,Sola, Lluis,Vidal-Ferran, Anton,Pericas, Miquel A.
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p. 5340 - 5353
(2008/12/20)
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- METHOD OF SYNTHESIZING KEY INTERMEDIATES FOR THE PRODUCTION OF CAMPTOTHECIN DERIVATIVES
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The present invention discloses a process for efficient production of 2-amino-5- hydroxypropiophenone corresponding to the AB ring part of camptothecin (CPT) skelton, which is a key intermediate useful for the total synthesis of camptothecin analogs including 7-Ethyl-10-hydroxy camptothecin and novel intermediates thereof.
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Page/Page column 8
(2010/11/25)
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- Axially chiral NHC-Pd(II) complexes in the oxidative kinetic resolution of secondary alcohols using molecular oxygen as a terminal oxidant
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(Chemical Equation Presented) Axially chiral N-heterocyclic carbene (NHC) Pd(II) complexes were prepared from optically active 1,1′-binaphthalenyl- 2,2′-diamine (BINAM) and H8-BINAM and applied in the oxidative kinetic resolution of secondary alcohols using molecular oxygen as a terminal oxidant. The corresponding sec-alcohols can be obtained in good yields with moderate to good enantioselectivities.
- Chen, Tao,Jiang, Jia-Jun,Xu, Qin,Shi, Min
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p. 865 - 868
(2007/10/03)
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- Enantioselective diethylzinc addition to aldehydes catalyzed by Ti(IV) complex of unsymmetrical chiral bis(sulfonamide) ligands of trans-cyclohexane 1,2-diamine
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Titanium(IV) complexes of bidentate trans-cyclohexane 1,2-diamine-based unsymmetrical chiral bis(sulfonamide) ligands were evaluated as catalysts for the asymmetric addition of diethylzinc to aldehydes. The reaction provided secondary alcohols in quantita
- Bisai, Alakesh,Singh, Pradeep K.,Singh, Vinod K.
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p. 598 - 601
(2007/10/03)
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- Dioxygenase-catalysed oxidation of disubstituted benzene substrates: Benzylic monohydroxylation versus aryl cis-dihydroxylation and the meta effect
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Biotransformations of a series of ortho-, meta- and para-substituted ethylbenzene and propylbenzene substrates have been carried out, using Pseudomonas putida UV4, a source of toluene dioxygenase (TDO). The ortho- and para-substituted alkylbenzene substrates yielded, exclusively, the corresponding enantiopure cis-dihydrodiols of the same absolute configuration. However, the meta isomers, generally, gave benzylic alcohol bioproducts, in addition to the cis-dihydrodiols (the meta effect). The benzylic alcohols were of identical (R) absolute configuration but enantiomeric excess values were variable. The similar (2R) absolute configurations of the cis-dihydrodiols are consistent with both the ethyl and propyl groups having dominant stereodirecting effects over the other substituents. The model used earlier, to predict the regio- and stereo-chemistry of cis-dihydrodiol bioproducts derived from substituted benzene substrates has been refined, to take account of non-symmetric subsituents like ethyl or propyl groups. The formation of benzylic hydroxylation products, from meta-substituted benzene substrates, without further cis-dihydroxylation to yield triols provides a further example of the meta effect during toluene dioxygenase-catalysed oxidations. The Royal Society of Chemistry 2006.
- Boyd, Derek R.,Sharma, Narain D.,Bowers, Nigel I.,Dalton, Howard,Garrett, Mark D.,Harrison, John S.,Sheldrake, Gary N.
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p. 3343 - 3349
(2008/09/16)
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- Polystyrene-supported (R)-2-piperazino-1,1,2-triphenylethanol: A readily available supported ligand with unparalleled catalytic activity and enantioselectivity
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(Chemical Equation Presented) A very active and highly enantioselective catalytic resin, designed for minimal perturbation of the catalytic center by the polymer matrix, has been assembled in two steps from (S)-triphenylethylene oxide, piperazine, and Merrifield resin and tested in the enantioselective ethylation of aldehydes. 1-Arylpropanols of 94-95% ee are obtained in high yield by the use of only 2 mol % of catalytic resin at 0°C for 4 h.
- Castellnou, David,Sola, Lluis,Jimeno, Ciril,Fraile, Jose M.,Mayoral, Jose A.,Riera, Antoni,Pericas, Miquel A.
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p. 433 - 438
(2007/10/03)
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- Tail-Tied Ligands: An Immobilized Analogue of (R)-2-Piperidino-1,1,2- triphenylethanol with Intact High Catalytic Activity and Enantioselectivity
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A functional analogue of (R)-2-piperidino-1,1,2-triphenylethanol was synthesized and anchored to different polymeric supports by a position remote from the active region. This strategy, leading to what we call a tail-tied ligand, allows for the achievement of the optimal transition state geometry in the catalytic process. The catalytic activity of the resulting heterogenized ligands was investigated by online FTIR analysis. The optimum polymer was assayed in the addition reaction of diethylzinc to a large family of aldehydes rendering essentially intact high catalytic activity and enantioselectivity compared to its homogeneous counterpart.
- Pericas, Miquel A.,Castellnou, David,Rodriguez, Israel,Riera, Antoni,Sola, Lluis
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p. 1305 - 1313
(2007/10/03)
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- 2-Amino-substituted 1-sulfinylferrocenes as chiral ligands in the addition of diethylzinc to aromatic aldehydes
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A simple and modulable access to a structural variety of enantiopure amino-substituted ferrocenyl sulfoxides and their use as chiral catalysts in the asymmetric addition of diethylzinc to aromatic aldehydes is described. Moderate to high enantioselectivit
- Priego, Julian,Garcia Mancheno, Olga,Cabrera, Silvia,Carretero, Juan Carlos
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p. 1346 - 1353
(2007/10/03)
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- Aminosubstituted tert-butylsulfinylferrocenes as a new family of chiral ligands: Asymmetric addition of diethylzinc to aldehydes
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A ready access to a new family of planar chiral ferrocenes, the (RFc,RS)-2-amino substituted 1-tert-butylsulfinylferro-cenes, is described; in the case of the sulfonamide series enantioselectivities of up to 96% were obtained in the
- Priego,Garcia Mancheno,Cabrera,Carretero
-
p. 2026 - 2027
(2007/10/03)
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- Highly Efficient Synthesis of Enantiomerically Pure (S)-2-Amino-1,2,2-triphenylethanol. Development of a New Family of Ligands for the Highly Enantioselective Catalytic Ethylation of Aldehydes
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The reaction of (S)-triphenylethylene oxide (3) with diisopropoxytitanium(IV) diazide in benzene solution at 70°C takes place readily in a completely regioselective and stereospecific manner to afford (S)-2-azido-1,2,2-triphenylethanol (6). Reduction of the azide by catalytic hydrogenation leads to (S)-2-amino-1,2,2-triphenylethanol (5) that, by N,N-dialkylation with 1,4-dibromobutane, 1,5-dibromopentane, 1,5-dibromo-3-oxapentane, α,α′-dibromo-o-xylene, and methyl iodide, affords the corresponding (S)-2-dialkylamino-1,2,2-triphenylethanols (7a-e). On the other hand, the reaction of 5 with benzyl bromide or 1-iodobutane takes place as a monoalkylation, leading to the corresponding (S)-2-alkylamino-1,2,2-triphenylethanols (8f,g). The performance of amino alcohols 7a-e as ligands for the catalytic enantioselective addition of diethylzinc to benzaldehyde has been studied, with enantioselectivities of 94-97% being recorded. The best performing ligands in this family, 7a [(S)-1,2,2-triphenyl-2-(1-pyrrolidinyl)-ethanol] and 7c [(S)-2-morpholino-1,2,2-triphenylethanol] have been studied in the addition of Et2Zn to a representative family of aldehydes. With 7a, a 96.6% mean ee is recorded for a family of 16 α-substituted aldehydes and a 92.8% mean ee for a family of six α-unsubstituted aldehydes. With 7c working on the same families of aldehydes, the mean enantioselectivities are 96.8% and 91.8%, respectively.
- Reddy, Katamreddy Subba,Sola, Lluis,Moyano, Albert,Pericas, Miquel A.,Riera, Antoni
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p. 3969 - 3974
(2007/10/03)
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- Chiral C2-symmetric 2,5-disubstituted pyrrolidine derivatives as catalytic chiral ligands in the reactions of diethylzinc with aryl aldehydes
-
Two kinds of chiral C2-symmetric 2,5-disubstituted pyrrolidlne derivatives having a β-aminoalcohol moiety have been successfully synthesized and their catalytic abilities of chiral induction have been examined in the reactions of diethylzinc wi
- Shi, Min,Satoh, Yukihiro,Masaki, Yukio
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p. 2547 - 2552
(2007/10/03)
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- High Catalytic Activity of Chiral Amino Alcohol Ligands Anchored to Polystyrene Resins
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Enantiomerically pure (2S,3S)-2,3-epoxy-3-phenylpropanol (3) has been anchored to Merrifield resins with different degrees of cross-linking and functionalization. The resulting epoxy-functionalized resins 4 have been submitted to completely regioselective
- Vidal-Ferran, Anton,Bampos, Nick,Moyano, Albert,Pericas, Miquel A.,Riera, Antoni,Sanders, Jeremy K.M.
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p. 6309 - 6318
(2007/10/03)
-
- A superior, readily available enantiopure ligand for the catalytic enantioselective addition of diethylzinc to a-substituted aldehydes
-
The lithium perchlorate-induced ring opening of (S)-triphenylethylene oxide (3) with secondary amines (piperidine (a), N-methylpiperazine (b), AT-phenylpiperazine (c) and morpholine (d)) takes place in a stereospecific and completely regioselective manner to afford CR)-2-(dialkylamino)-l, 1, 2-triphenylethanols (4a-d). These amino alcohols catalytically induce the addition of diethylzinc to benzaldehyde with high enantioselectivity at 0 °C and at room temperature. Ligand 4a, which provides the highest enantioselectivity at 0 °C, has been studied in the addition of Et2Zn to a family of 20 representative aliphatic and aromatic aldehydes 5a-t. For a 17-membered set of a-substituted substrates (5a-m, q-t), including ortho-, meta-, and para-substituted benzaldehydes, the naphthaldehydes, ct./i?-unsaturated and aliphatic (cyclic and acyclic) aldehydes, the mean enantiomeric excess of the resulting alcohols 6a-m, q-t is 97%, whereas for three a-unsubstituted specimens (5n-p) the addition takes place with an enantioselectivity of 92-93%.
- Sola, Lluis,Reddy, Katamreddy Subba,Vidal-Ferran, Anton,Moyano, Albert,Pericàs, Miquel A.,Riera, Antoni,Alvarez-Larena, Angel,Piniella, Joan-F.
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p. 7078 - 7082
(2007/10/03)
-
- Synthesis and activity of 2-methyl-3-aminopropiophenones as centrally acting muscle relaxants
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Some novel 2-methyl-3-aminopropiophenones were synthesized and their centrally acting muscle relaxant activities were,evaluated for an inhibitory effect on the flexor reflex in rats. The structure-activity relationships are discussed. In this series 2-methyl-3-pyrrolidino-1-(4-trifluoromethylphenyl)-propan-1-one (28) showed significant centrally acting muscle relaxant activity. In addition, the activities of each enantiomer (28-(S) and (R)) were studied along with their acute toxicities. Compound 28-(R) was found to exhibit more potent activity and weaker acute toxicity than 28-(S). Accordingly, compound 28-(R) (NK433) is under development as a novel centrally acting muscle relaxant.
- Shiozawa,Narita,Izumi,Kurashige,Sakitama,Ishikawa
-
-
- Chiral C2-Symmetric 2,5-Disubstituted Pyrrolidine Derivatives as Chiral Catalyst Ligands in the Reaction of Diethylzinc with Arylaldehydes
-
Two kinds of chiral C2-symmetric 2,5-disubstituted pyrrolidine derivatives having a β-aminoalcohol moiety were successfully synthesized and their catalytic abilities of asymmetric induction were examined in the reaction of diethylzinc with aryl
- Shi, Min,Satoh, Yukihiro,Makihara, Takechi,Masaki, Yukio
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p. 2109 - 2112
(2007/10/03)
-